The present invention relates to forming a sample section and working a TEM sample by use of a focused ion beam apparatus.
Using FIG. 9, explanation is made on an observation method of working a defect region with use of a conventional FIB-SEM apparatus. At first, a sample 22 is worked by irradiating an ion beam IB, to form a rectangular opening 21. After forming the opening, an electron beam EB is scan-irradiated to a section D. By detecting a secondary electrons generated at that time, a secondary electron image is observed as to the section D. In order to acquire a section through a defect center in defect analysis, two points are specified in an end of a particular structure within an acquired secondary electron image. Then, the particular structure is gradually milled by an ion beam IB, to measure the end-to-end distance of the specific structure in the milling. By terminating the milling with the ion beam IB at a time the change of distance becomes nearly zero, a section can be acquired in the center region of the defect.
[Patent Document 1] JP-A-H11-273613
In the foregoing defect observation-by-working method using the conventional FIB-SEM apparatus, there is a need to irradiate an electron beam to a sample section in order to detect a center position of a defect or a contact hole. This requires an FIB-SEM apparatus having a SEM column. Meanwhile, because of working with an FIB and confirming an end point by switching the irradiation beam to SEM, it takes time in switchover. The present invention is to provide a sample section forming method for effectively detecting a center position of a defect or a contact hole even with an FIB apparatus not having a SEM observation function. Meanwhile, it is an object to provide a method to efficiently prepare a thin-piece sample such that the center of a defect or a contact hole comes to a center of an observing thin-piece sample for a TEM or the like.